JWCN_V2_N3_RP5 S. Sudha L. Gowthami Journal On Wireless Communication Networks 2320 - 2351 2 3 28 32 WSN, LPL, GIS, CSMA (Carbon Sense Multiple Access, Mobile Sensor Unit Every day, lakhs of devotees gather in Tirupathi.. Tracking the movement of such a large number of people is crucial to the devotees them-selves and the authorities managing the whole event. This letter reports a real-time devotee tracking system that has been designed and implemented. The system relies on a dedicated delay-tolerant wireless sensor network (WSN). This WSN is interfaced to the Internet through gateway(s) available from an internet service provider (ISP) . Energy efficiency, robustness, and reliability are key factors in the design of the system. Each devotee is given a mobile sensor unit which includes a GPS chip, a microcontroller, and antennas. A network of fixed units is installed in the Holy area for receiving and forwarding data. Periodically, each mobile unit sends its user identification (UID), latitude, longitude, and a time stamp. A central server maps the latitude and longitude information on a geographical information system (GIS). The developed system can be used to track a specific or a group of devotees. October - December 2013 Copyright © 2013 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2557